Western Caribbean disturabance 94L bringing heavy rains; Lupit's path uncertain

By: Dr. Jeff Masters , 2:39 PM GMT on October 21, 2009

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A broad 1008 mb low pressure area has developed near 10N 84W, inland over Costa Rica. NHC designated this disturbance Invest 94L yesterday, but is no longer issuing model products for the disturbance. This morning's QuikSCAT pass showed a broad circulation around the low, with top winds of about 30 - 35 mph over the extreme Southwestern Caribbean. Obviously, the center will have to move over water in order for significant development to occur, but recent satellite loops show that the low is pulling in an increasing amount of moisture from the Pacific, leading to heavy rains over Costa Rica and western Panama. Wind shear is low, about 5 - 10 knots, and there is deep layer of high moisture over the entire Western Caribbean, which both favor development if the center moves over water. Rainfall estimates from the Navy Research Lab indicate that 94L dumped up to three inches of rain over portions of Panama, Costa Rica, and Nicaragua over the past 24 hours.


Figure 1. Morning satellite image of Invest 94L.

The forecast for 94L
Wind shear is expected to remain in the low to moderate range, 5 - 15 knots, for the next five days in the Western Caribbean. Sea Surface temperatures are very warm, 29°C, and there is plenty of moisture through a deep layer of the atmosphere. The only major impediment to 94L becoming a tropical storm later this week would seem to be proximity to land. At present, only the GFS model develops 94L, but weeks it very weak. The GFS predicts the storm will take a north then northwesterly track across western Cuba early next week, then into the Gulf Coast of Florida later in the week. However, it is equally likely that 94L will stay bottled up in the Western Caribbean for the foreseeable future. I'll continue to give 94L a medium (30 - 50% chance) of eventually becoming a tropical depression over the next ten days. NHC is giving 94L a low (less than 30% chance) of developing into a tropical depression by Friday, which is a good forecast. Given 94L's current state of disorganization and location over land, Saturday is the earliest we should expect it to organize into a tropical depression. NHC has not put the Hurricane Hunters on call to fly 94L Thursday or Friday.

Rick misses Baja, hits Mainland Mexico near Mazatlan
Tropical Storm Rick made landfall near 10am EDT in Mainland Mexico just north of Mazatlan. Top winds measured at the Matatlan airport during landfall were 39 mph, gusting to 61 mph. The primary threat from Rick will be heavy rains of up to six inches in the mountains near Mazatlan. Rick's remains should being at most one inch of rain to south-central Texas on Thursday.

Typhoon Lupit weakens and slows; path now uncertain
Typhoon Lupit, now a Category 1 storm with 90 mph winds, continues to have difficulty dealing with a slug of dry air it wrapped into its core two days ago. Microwave imagery showed that the typhoon was missing a portion of its northern eyewall this morning. However, recent Infrared satellite loops show that the eye has warmed and become more distinct, a sign of intensification. Also, the cloud tops of Lupit's eyewall have cooled in recent hours, signaling that they are more vigorous and reaching higher into the atmosphere. Lupit is in an environment favorable for re-intensification, with low wind shear of 5 - 10 knots and warm sea surface temperatures of 28 - 29°C. It would not be a surprise to see Lupit intensify into a major Category 3 typhoon again by Thursday, though the official forecast from the Joint Typhoon Warning Center is less aggressive, calling for a Category 2 storm by tomorrow. Even in its current weakened state, Lupit is a prodigious rain-maker, with rainfall rates exceeding one inch per hour near its core (Figure 2).

The future path of the typhoon is now highly uncertain, as steering currents are weakening and the storm is slowing down. A weakness in the ridge of high pressure steering Lupit west-southwest is developing, and several models (ECMWF, GFS) now predict recurvature of the typhoon before it reaches the Philippines. This optimistic scenario is counterbalanced by the very pessimistic forecasts of the UKMET and NOGAPS models, which take the typhoon inland over the northern portion of Luzon 1 - 2 days from now, and then stall the storm for 2 - 3 days. This would cause a major flooding disaster, as the soils are already saturated and the dams completely full from the 20+ inches of rain dumped by Super Typhoon Parma in early October. If Lupit stalls for several days over Luzon, it would dump another 20+ inches of rain, triggering massive flash flooding and life-threatening mudslides.

Storm chased Jim Edds is in northern Luzon to document Lupit's landfall, and has some interesting photos of the preparations the residents are taking.


Figure 2. Rainfall rates observed by a polar-orbiting microwave satellite at at 10:24 UTC Wednesday 10/21/09. Lupit is expected to dump rains in excess of one inch per hour (red and pink colors) along its path. Up to 12 inches of rain in a 24-hour period are expected from the typhoon. Image credit: Navy Research Lab, Monterey..

I'll have an update Thursday morning.

Jeff Masters

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Quoting Weather456:


to the north
When is it suppossed to let up?
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System in sw Caribbean looks to be getting better organized this afternoon.
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Quoting Seastep:


College road-trips are always fun. It's part of the experience.


haha exactly, so pictures should prolly have a warning on them :P
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385. 786
well the EPac vort is drifting East and the SW Carib vort drifting N..sounds like a battle of wills
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Quoting Floodman:


Oh lord, is it ever...someone knew how to deal with stormtop in the old days, huh?
I did not know of Dr.Masters blog until September 07. I have not had time to go back and read all the cool posts. Hopefully I can do that someday. I wonder how far back in time the archives go? do you know this?
Member Since: September 27, 2007 Posts: 1 Comments: 21183
Quoting futuremet:


Many don't realize that it is because of the change in forecast in steering currents that some of the models dropped this system. The CMC and the ECMWF are now expecting the development of a more pronounced ridge over the east coast. This causes the moisture to move over land--hampering tropica cyclogenesis. However, notice how the CMC reinvigorates it in the Gulf.

I personally am leaning with the ECMWF and the CMC.
Will this be a GOM storm?
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Quoting stormsurge39:
456 is there a high pressure East of AOI?


to the north
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Quoting tornadodude:
so I got some friends to go with me to the game tomorrow, definitely excited


College road-trips are always fun. It's part of the experience.
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380. 786
I ask becuase from the vort. map looks like they are more joined than before
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Quoting 786:
what about the vorticity in the Atlantic? looks pretty circular...

the vort. has become more organised then with 94L..i guess we will see what nightfall brings


To me, it's one big area of low pressure with two vort centers....something gotta give as the Atlantic low drifts north.
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so I got some friends to go with me to the game tomorrow, definitely excited
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Quoting Weather456:
The Eastern Pacific low is being pulled eastward

456 is there a high pressure East of AOI?
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375. 786
so until the Epac low is pulled away not much the SW Carib. low can do. Can the EPac low pull the SW Carib low with it?
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NASA GOES loops shows a low level circulation east o Nicaragua and another circulation south of Costa Rica.
Member Since: October 28, 2006 Posts: 57 Comments: 30489
373. 786
what about the vorticity in the Atlantic? looks pretty circular...

the vort. has become more organised then with 94L..i guess we will see what nightfall brings
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The Eastern Pacific low is being pulled eastward

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Quoting Weather456:


And if you read some of the posts from around 1 pm, you would realize that all of the vorticity both in the EPAC and SW Caribbean ends back up in the latter, per the GFS. Hows this so? Well look at the low in the EPAC, its stationary, that should tell you alot considering they normally head wnw away from Panama/Costa Rica.
ok thanks
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Quoting Grothar:


Must have been posting when you were. Weather in my image right above your entry, it looked like two vortices to me. Is is just my eyes?


look at post 564
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369. 786
Ike ...thanks
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Quoting stormsurge39:
So you see this to be an Atlantic Storm? Im getting a little confused, because some of the people that were saying that 94L was an Atlantic storm yesterday, say different today!


And if you read some of the posts from around 1 pm, you would realize that all of the vorticity both in the EPAC and SW Caribbean ends back up in the latter, per the GFS. Hows this so? Well look at the low in the EPAC, its stationary, that should tell you alot considering they normally head wnw away from Panama/Costa Rica.
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367. IKE
When looking at vorticity look in the upper left hand corner of the page. You can go back 3 hours...then another 3 hours...and so forth...

Here's 1200UTC....




1500UTC....




1800UTC....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting Weather456:


You can do this by comparing the vorticity patterns over the past 24 hrs....


Must have been posting when you were. Weather in my image right above your entry, it looked like two vortices to me. Is is just my eyes?
Member Since: July 17, 2009 Posts: 71 Comments: 26118
365. xcool



Member Since: September 26, 2009 Posts: 2 Comments: 15670
Winter Weather Advisory

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE CARIBOU ME
ISSUED BY NATIONAL WEATHER SERVICE GRAY ME
307 PM EDT WED OCT 21 2009

...ACCUMULATING SNOW WILL AFFECT NORTHERN MAINE TOMORROW...

.A LOW PRESSURE SYSTEM WILL TRACK OUT OF THE GREAT LAKES REGION
AND ACROSS CENTRAL MAINE DURING THE DAY TOMORROW. AS THE LOW MOVES
THROUGH CENTRAL MAINE SNOW WILL DEVELOP ON THE BACKSIDE OVER
EXTREME NORTHERN MAINE. THIS SYSTEM WILL MOVE QUICKLY OFF TO THE
EAST LATE THURSDAY. HOWEVER...IT WILL GENERATE 3 TO 6 INCHES IN
JUST A FEW HOURS AS IT MOVES THROUGH.
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363. 786
thanks 456 I can't see more of a shift toward the SW Caribbean just warping of the broad low but of-course I'm only learning. From the vorticity map you posted looks like the EPac has a stronger vort.? All various weather reporters are still holding on to the Northern movement Sunday or Monday. Last night we had some torrential rains in Cayman with some good gusts, we are starting to see some blue skies which could be the result of a shift Southward.
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Quoting stormsurge39:
So you see this to be an Atlantic Storm? Im getting a little confused, because some of the people that were saying that 94L was an Atlantic storm yesterday, say different today!


It appears that the majority of the energy from 94L transitted Central America and is in the EPAc right now...there is some indication that it will move back into the SW Carib in the next 24-36 hours
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Quoting stormsurge39:
So you see this to be an Atlantic Storm? Im getting a little confused, because some of the people that were saying that 94L was an Atlantic storm yesterday, say different today!



Read my blog today and over the past several days....I have never drifted from the fact that this was going to drift north over the Western Caribbean Sea.

You see some people flip flop based on models, not able to to pick up any patterns from actual data.

Last night’s QuikSCAT pass also places the low either near the coast or over Costa Rica itself. However, the latest satellite imagery proposed the low might have drifted more along the coast. This should delimit development in the meantime but the low is expected to slowly drift back over the SW Caribbean.
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Quoting Weather456:
Look at where the vorticity is heading...SW Caribbean



Look at 72 hrs





Now several of us reinforced the fact that much of the 850 vort will end back in the SW Caribbean...now we wait for the 18Z forecast maps






Surely looks like it's starting to establish a singular low level circulation per my tracking today.
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Quoting Weather456:
Look at where the vorticity is heading...SW Caribbean



Look at 72 hrs





Now several of us reinforced the fact that much of the 850 vort will end back in the SW Caribbean...now we wait for the 18Z forecast maps



So you see this to be an Atlantic Storm? Im getting a little confused, because some of the people that were saying that 94L was an Atlantic storm yesterday, say different today!
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Quoting Floodman:


Oh lord, is it ever...someone knew how to deal with stormtop in the old days, huh?


Ya tie him up to the horse trof and through mud at him.
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What do you make of this. It looks like another swirl. I could not post the animated version.
Member Since: July 17, 2009 Posts: 71 Comments: 26118
Quoting 786:
456, how can u tell the vorticity is headed toward SW Caribbean? I have an untrained eye


You can do this by comparing the vorticity patterns over the past 24 hrs....
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Quoting Floodman:


Oh lord, is it ever...someone knew how to deal with stormtop in the old days, huh?


um, I actually thought that stormtop made that handle haha
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2 vort centers at the surface

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Quoting Weather456:
Look at where the vorticity is heading...SW Caribbean



Look at 72 hrs





Now several of us reinforced the fact that much of the 850 vort will end back in the SW Caribbean...now we wait for the 18Z forecast maps





Many don't realize that it is because of the change in forecast in steering currents that some of the models dropped this system. The CMC and the ECMWF are now expecting the development of a more pronounced ridge over the east coast. This causes the moisture to move over land--hampering tropica cyclogenesis. However, notice how the CMC reinvigorates it in the Gulf.

I personally am leaning with the ECMWF and the CMC.
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Quoting hydrus:
that is so stupid it really is funny. Referring to the stormtop post...


Oh lord, is it ever...someone knew how to deal with stormtop in the old days, huh?
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351. xcool
lol
Member Since: September 26, 2009 Posts: 2 Comments: 15670
Quoting AwakeInMaryland:
333. T-Dude, just to let you know "they" won't us quote this post. So I just want to know that if you get banned today, know that it was so worth it. And if we never see you again, you will always be in our hearts, as a lost brave son of Wunderland.

You too, Grothar. When you going to make the curtain your avatar, maybe wearing leather, a helmet and shades.

I'm going to get banned right along with you after this. Oh well, worth it.


haha totally worth getting banned, not much happening anyway
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349. 786
456, how can u tell the vorticity is headed toward SW Caribbean? I have an untrained eye
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Quoting Floodman:


Okay, so I'm not the most militant around here when it comes to trolls...LMAO
that is so stupid it really is funny. Referring to the stormtop post...
Member Since: September 27, 2007 Posts: 1 Comments: 21183
Quoting AwakeInMaryland:

How/where did you FIND this stuff?
(I know I said I wouldn't come on in afternoons anymore but waiting for son EvilDamien to call from Hawaii. Can't. Stop. Laughing.)


Didn't tornadodude warn you about the afternoons. They can get rufffffff for a lady. Although, it has been pleasant today.
Member Since: July 17, 2009 Posts: 71 Comments: 26118
333. T-Dude, just to let you know "they" won't let us quote this post. So I just want to know that if you get banned today, know that it was so worth it. And if we never see you again, you will always be in our hearts, as a lost brave son of Wunderland.

You too, Grothar. When you going to make the curtain your avatar, maybe wearing leather, a helmet and shades.

I'm going to get banned right along with you after this. Oh well, worth it.
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345. 786
Current Weather Conditions:
Puerto Limon, Costa Rica

4 PM (20) Oct 21 84 (29) 73 (23) 29.71 (1006) N 6
3 PM (19) Oct 21 84 (29) 73 (23) 29.73 (1006) NNE 6
2 PM (18) Oct 21 84 (29) 73 (23) 29.77 (1008) N 5
1 PM (17) No Data
Noon (16) Oct 21 82 (28) 75 (24) 29.83 (1010) N 9
11 AM (15) Oct 21 84 (29) 73 (23) 29.83 (1010) NNW 6

10 AM (14) Oct 21 82 (28) 73 (23) 29.82 (1009) WNW 3
9 AM (13) Oct 21 75 (24) 73 (23) 29.81 (1009) SW 5
8 AM (12) Oct 21 73 (23) 71 (22) 29.8 (1009) SW 5


check out the pressure and the wind shifts!

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Quoting Floodman:


Okay, so I'm not the most militant around here when it comes to trolls...LMAO


HAHA
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Look at where the vorticity is heading...SW Caribbean



Look at 72 hrs





Now several of us reinforced the fact that much of the 850 vort will end back in the SW Caribbean...now we wait for the 18Z forecast maps



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Quoting Grothar:


They were for real????


yes LOL
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Quoting tornadodude:


here, just search the archives, this was like 3 or 4 days after I joined.
posts 483 and 487

link


They were for real????
Member Since: July 17, 2009 Posts: 71 Comments: 26118
Quoting tornadodude:
487. ST0RMT0PSmom 7:38 AM GMT on July 01, 2006 Hide this comment.
STORMTOP IVE TOLD YOU NOT TO POST ON HERE YOU NAUGHTY SON! I WILL HAVE PAPA STORMTOP DEAL WITH YOU AS SOON AS I RUN YOUR COMPUTER OVER WITH MY CAR.


Okay, so I'm not the most militant around here when it comes to trolls...LMAO
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Quoting Weather456:
Good afternoon to all


Hey Weather!!
Member Since: July 17, 2009 Posts: 71 Comments: 26118

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.